Rolling mill



L. IVERSEN I ROLLING MILL Dec. 8, 1936.

Filed Jan. 24, 1934 5 Sheets-Sheet 1 INVENTOR Dec. 8, 1936.

L. IVERSEN ROLLING MILL INVENTOR L. IVERSEN Dec. 8, 1936.

ROLLING MILL Filed Jar}. '24, 1934 5 Sheets-Sheet 3 No WW 1 NM MWINVENTOR Patented Dec. 8, 1936 UNITED STATES ROLLING lVHLL Lorenz.Iversen, Pittsburgh, Pa.

assignor to Mesta Machine Company, Pittsburgh, Pa., a corporation ofPennsylvania 4 K Application January 24, 1934, Serial No. 708,097

9 Claims.

My invention relates to rolling mills and in particular to a verticalmill adapted to cooperate with the last stand of a continuous bar millin the production of bars shaped and dimensioned to a high degree ofprecision.v

It is sometimes desired to give bars a pass through a stand of verticalrolls after passing the last stand of the usual grooved horizontalrolls, for precision sizing of the product. Vertical mills of this typeheretofore have been driven from below by a line shaft through bevelgearing. This type of construction is heavy and cumbersome, andtherefore diflicultrto assemble as well as to adjust and. maintain. Theold construction has been objectionable also for the reason that itprevents the vertical mill from being placed close up to the last standof horizontal rolls which is always desirable. The mechanical drive,furthermore, is inflexible as to ratio between diameters of thehorizontal and vertical rolls to maintain a predetermined ratio betweenperipheral speeds which is always necessary, depending on the amount ofreduction effected by the vertical rolls. Such drive also makesdiflicult the removal of the mill when not needed.

Ihave invented a vertical mill of the char acter mentioned whichovercomes the above recited objections to such devices as knownheretcfore, and in addition is characterized by further novel and usefulfeatures which will become apparent as the description thereof proceeds.

In accordance with my invention, I provide a supporting base or frame inwhich are removably. and adjustably positioned a pair or roll units orhousings each including a vertically adjustable roll shaft, a drivingmotor and powertransmission gearing. The construction is such that thevertical rolls may be positioned quite closely to the last stand ofhorizontal rolls. Provisions are made for easily efiecting all thedesired adjustments of rolls and the individual motor drive makes itpossible to'have the peripheral speed of the vertical rolls conform ex-.actly with that of the horizontal rolls, regardless ofany changes inthe ratio of the roll diameters. The entire structure can readily bere,- moved when desired, since the drive is a-unit with the roll and itssupporting housing.

My invention also contemplates an automatic control system forregulating the speed of the vertical rolls to maintain their peripheralspeed exactly the same as that of the horizontal rolls.

To this end. I preferably employ synchronous alternating current motorsfor driving the verholder.

' tical rolls and I supply power to such motors from a generator drivenby a variable speed motor. A regulator is effective to change the speedof the generator-driving motor in case the ratio of the speeds of thevertical and horizontal rolls 5 departs from a predetermined value.

For a complete understanding of the invention, reference is made to theaccompanying drawings illustrating a present preferred embodiment. Inthe drawings- 1 Figure 1 is a side elevation of the vertical mill of myinvention associated with a stand of horizontal rolls, specifically, thelast stand of a continuous bar mill;

Figure 2 is a half section alongthe line 11-11 of Figure 1; I

Figure 3 is a sectional view along the line III--III of Figure 2;

Figure 4 is a partial sectional viewalong the line IV-JV of Figure 2; 20

Figure 5 is a schematic diagram showing the mill drive and the speedcontrol apparatus; and

Figure 6 is a partial sectionalview along the line VIVI of Figure 3.

Referring in detail to the drawings, the last stand of a continuous barmill is shown at Hi.

- of the base rest on a beam l8 supported on any convenient foundation.

Feet I9 on the other side of the base are bolted directly to the bedplate I? of the mill l0.

A pair of similar roll units 20 and 2| are slidably supported on theways I 6 of the base l5. Each of these units comprises a generallyboxlike casting 22 having a shelf 23 projecting out- 40 wardly thereof.Bearings 24 within the casting 22 support a worm wheel 25 coaxiallythereof. The lower bearing 24 is held in position by a sleeve 26telescoped into the lower end ofthe casting 22. The sleeve 26 isthreadedinternally 45 to receive a bearing holder 21 correspondinglythreaded. A thrust bearing 28 is seated in the holder '21 for supportingthe lower end of a vertical shaft 29 therein. The bearing .28 is securedin the holder by a spur gear 3F b lted 'to the 50 The shaft 29 is'splined to the worm wheel 25, permitting vertical movement of the shaftrelative to the wheel. The upper end of the shaft .29 is journaled in aroller bearing 3|, which also 55 of the shaft 29 and roll 32 carriedthereon. This adjustment can be effected by means of a shaft 35projecting upwardly and outwardly from the lower part of the casting 22,and having a squared end for cooperation with a wrench. The shaft 35carries a bevel pinion 36 at its lower end mesh-- ing with the gear 30bolted to the holder 27.

The bottom of the casting 22 is closed by a cover 31 and an oil pump 38on the lower end of the shaft 29 circulates oil from the cover, whichserves as a reservoir, to all the working parts of the unit 29.

A motor 39 mounted on the shelf 23 drives a worm shaft lfl journaled inbearings 58a seated in the walls of the casting 22. It will be observedthat the worm shaft ill] and the axis of the motor 3% are at an obliqueangle to the path of material through the mill. This, permits the lengthof the mill in the direction of said path to be shortened and the entireconstruction made more compact. Both units are identical, furthermore,and are therefore interchangeable.

, The worm shaft til meshes with the worm wheel 25 and thereby drivesthe shaft 29 and the roll 32. It will be understood that the units 28and 25 are identical as to the parts so far described.

The units 20 and 2i on opposite sides of the bearings 3! are providedwith transverse bores 3i and t2 respectively. A tube 33 is seated inenlargements M of the bores All and t2. A screw shaft 5S5 extendsthrough the bores and the tube. The end of the shaft is threaded forengagement with a nut 36 seated in the unit 28. A spring ll in the tube33 is compressed between a ring 38 \bearing against the end of theenlargement of the bore ll, and a ring 6Q abutting a sleeve 58 bearingon the end of the enlargement of the bore d2. A collar 5! is threadedinto the end of the tube l3. It will be apparent that the parts justdescribed constitute a spring cushion for yieldingly forcing the unitsapart and that rotation of the shafts 55 will adjust the units toward oraway from each other. The two screw shafts 45 on opposite sides of thebearings 53! may be simultaneously adjusted by means of a shaft 52,having a squared end for cooperating with a wrench, and a pinion 53. Thepinion 53 meshes with gears 54 and these in turn mesh with gears 55 onthe ends of the screw shafts t5.

The two units being adjustably held in a predetermined spaced relationrelative one to another by the means just described, may be adjustedtogether laterally of the base so as to line up the pass between therolls 32 with that between the horizontal rolls it. For this purpose Iprovide a screw shaft 56, the outer end of which is journaled in athrust bearing 5i! at the end of the ways is on the exit side of themill. An angle bar 58 shown more clearly in Figure 6 is bolted to theoverhanging edge of the unit 2!. operation with the threaded portion ofthe shaft 56. The inner end of this shaft is journaled in a longitudinalbore through the way it. Rotation of the shmt dd applies lateral thrustta the The bar 58 is threaded at 59 for 00-" unit 2i and thereby movesboth units as an integral whole along the ways it. The end of the shaft56 is squared for receiving a wrench to make this adjustment.

It has long. been known that vertical rolls for working bar stock mustbe driven at precisely the same peripheral speed in order to preventlateral deflection of the bars as they emerge from the pass between therolls. It is for this reason that vertical rolls have previously beendriven from a common transverse drive shaft through suitable gearing,and introduced structural complications as before mentioned. Byproviding individual motor drives for both the rolls of the mill of myinvention, I avoid the structural complications characteristic of theold mechanical drive and the necessity that the vertical roll diametersbear a fixed ratio to the diameters of the horizontal rolls determinedby the ratio of the gearing therebetween. I preferably employalternating-current motors of the induction type to drive the rolls atthe same speed, the rolls being turned to precisely the same diameter. Isupply the motors 39 with polyphase alternating current from a commonsource. The motors, being similar in design, operate in synchronism andthe rolls 32 always turn at the same speed.

I utilize a special polyphase, alternatingcurrent generator as a sourceof current for the motors 3t and drive the generator by a variablespeedmotor to make possible a highly flexible control of the speed of therolls 32. The arrangement of the power apparatus and the controltherefor are illustrated diagrammatically in Figure 5, wherein parts ofmechanism which have already been mentioned have the same referencenumerals used hereinabove.

Referring in detail to Figure 5, it will be seen that the motors 39driving the vertical rolls 32 are connected in parallel to analternating current generator Bil. The usual switches or circuitbreakers are omitted from Figure 5, for the sake of clearness. Thegenerator 60 is connected to a driving motor 63 preferably of thedirect-current, compound-wound type, having a series field winding 52, ashunt field winding 53, a field rheostat B t and a speed-controlresistor 65 connected in series with the shunt field winding. The motor6i derives energy from a direct-current bus 66 through suitable circuitbreakers not shown.

The rolls B3 are driven bya motor 61 which may conveniently be similarto the motor 6|, being of the usual compound-wound type with a shuntfield rheostat for speed control. In the usual practice, the speed atwhich the motor 6'! drives the rolls l 3 is determined by the design ofthe mill as a whole, and is ordinarily not subject to materialvariation. For the purpose of coordinating the speed of the rolls 32with that of the rolls I3, therefore, the speed of the rolls 83 may beassumed constant.

It will be obvious from the description already given that the controlsystem of my invention makes it possible to vary the speed of the rolls32 to provide the desired ratio to the speed of the rolls l3 bycontrolling the speed of the motor 6! through the shunt field rheostat64. Any change in the speed of the motor 8! changes the frequency of thegenerator 60, and thereby, the speed of the motors 39. The system thusprovides great flexibility of control of the speed of the verticalrolls. Regardless of the relative diameters of the vertical andhorizontal rolls, it is only necessary to vary the speed of the motor 6!to drive the rolls 32 at the same peripheral speed as the rolls [3 or ata speed which bears a desired ratio to that of the rolls l3. Since therolls 32 are always driven at the same speed, there can be I foraccurate, continuous control of the speed of .To this end, I providepilot generators the vertical rolls to overcome any slight departure ofthe ratio-between the speeds of the vertical horizontal rolls from thepredetermined value. 68 and 69 connected to a synchroscope 10 or otherequivalent device. The generator 68 is driven fromthe rolls l3. Thegenerator 69 generator 60 through a hydraulic drive including avariable-displacement pump H and a simi lar motor 12 connected by ahydraulic circuit 13. The hydraulic drive is adjust-able and permits thespeed of the generator 69 to be matched with that of the generator 68,regardless of the relative angular velocities of the rolls l3 and therolls 32. The generators 68 and 69 have constant excitation and generatealternating voltages transverse drive shaft previously. is entirelyeliminated, together with of frequencies directly proportional to thespeeds at which they are driven. These frequencies may be equalized fora common peripheral speed of the rolls l3 and 32, by adjusting thehydraulic drive.

In order to insure that the surface speed of the vertical rolls isslightly greater than the surface speed of the horizontal rolls, itis-only necessary to speed up the motor 6| by field weakening until thesynchroscope 10 revolves in the direction which indicates that theprecision mill is running faster than the horizontal mill. There is thusno stubbing tendency when the piece enters the vertical mill. As soon asit enters, however, the load imposed on the vertical mill.will slow itdown to a point where it is at the proper speed to receive the bar fromthe horizontal mill and deliver it at a speed as much higher as requiredby the ratio of reduction in the vertical stand.

It will be obvious that the invention described and illustrated hereinis characterized by numei\ous advantages over anything known to theprior art. In the first place, the cumbersome which has been used itsassembly, adjustment and maintenance difficulties. The vertical mill ofmy invention, furthermore, is adapted to be positioned very close to thelast stand of a continuous mill, and in fact rests partly on the veryfoundation thereof. Each of the vertical rolls may be adjustedvertically with respect to the other to properly line up the grooves inthe roll faces. The roll units, furthermore, may be adjusted toward andaway from each other to provide the proper size of pass, and the twounits shifted simultaneously in a single direction to line up the passwith that between the horizontal rolls. The means for effecting allthese adjustments are simple, easily operable and readily accessible.These adjustments, furthermore, may be made so accurately that the millmay be correctly described as a precision machine. Since the rolls areoverhung, thatis, both the shaft bearings are on the same side of theroll, roll changing is greatly expedited and facilitated. I

It is not necessary to clamp the parts in adjusted position since alladjustments are selflocking. At the same time, they can be operated witha minimum of effort. Each of the roll units is entirely self-containedand oil-tight, all

is driven from the] entire roll units themselves may be readily removedfrom the supporting base if this becomes necessary.

It is not necessary to disconnect the couplings, since the drivingmotors are mounted directly on shelves extend'ng laterally of the rollunits.

There are no cross shafts, bevel gears, stuffing boxes or the like torequire expensive and con tinuous maintenance. The, vertical rolls areelectrically synchronized so that straight delivery of the material isinsured. The entire unit may be lifted out when not required, as whenrolling I products not requiring precision shaping and sizing. v 7

While I have illustrated and described but a single preferred embodimentof the invention, it will be apparent that many changes therein may bemade without departing from the spirit of the invention or the scope ofthe appended claims.

I claim:

1. In a rolling-mill, a base, a'pair of verticallydisposed, roll-shaftcasings slidable horizontally thereon, a pair of spaced shaft bearingsseated in an axial bore in each casing, means for resiliently forcingthe casings apart, a tie rod extending through both the casings forlimiting the separation therebetween, and means for adjusting one ofsaid casings relative to the other.

2. In a rolling mill, a base, a pair of roll-shaft casings adjustablethereon, means extending through the casings to limit the separationtherebetween, means between the casings for yieldingly urging themapart, and means for adjusting one of said casings along the base.

3. A rolling mill comprising a base, a pair of similar housingsadjustably secured to the base, each housing including a shaftjournalled substantially vertically therein, a roll mounted on theshaft, a shelf extending laterally from the housing, a motor mounted onthe shelf with its axis substantially horizontal, and gearing providingdriving connection between the motor and said shaft, the rolls of thetwo housings cooper-' ating to define a pass for material to be rolled/each of said housings and its motor being removable from the baseindependently of the other.

4. The apparatus defined by claim 3 wherein said base is open at the topand said housings are suspended therein for removal verticallytherefrom.

5. The apparatus defined by claim 3 characterized by means supportingsaid base, the base being removably secured to said means whereby thebase and said units may be removed while maintaining a predeterminedrelation of the rolls and without-disconnecting the motors from theirdrives.

6. In a rolling mill adapted to cooperate with the last stand of acontinuous mill driven at substantially constant speed, astand offinishing rolls adjacent said last stand, a variable speed drive for thefinishing stand, means for indicating the relative peripheral speeds ofthe rollr of said last stand and said finishing stand, said indicatingmeans including means driven at speeds proportional to those of the laststand and thereto, whereby to compensate said indicating means forvariations in the diameters of the rolls of said stands.

7. In a rolling mill, a base, ways extending therealong, a pair ofsimilar roll units adjustable on said ways, each of said units includinga closed housing, a vertical roll shaft journaled therein, a shelfextending laterally from the housing, a motor mounted on the shelf withits axis horizontal, and Worm and Worm wheel driving gears between themotor and shaft, said housings being parallel, the drive and housing ofeach unit being independent of the other whereby either of said units isremovable from said base independently of the other.

8. In a rolling mill, a base, a pair of similar roll-shaft housingscarried on horizontal ways on the base for adjustment thereon, eachhousing having a laterally extending shelf, motors mounted on saidshelves and disposed with their axes horizontal and oppositely inclinedat an oblique angle to the path of material through the mill, a rollshaft journaled in each of said housings, one of said motors beinggeared to each shaft, said housings both being removable from the baseindependently of the other.

9. The apparatus defined by claim 3 characterized by each housing havinga segmental nut secured thereto and a screw shaft journaled in said basecooperating with said nuts.

LORENZ IVERSEN.

